Elise Furlan (IPAC) - The Herschel Orion Protostar Survey: Constraining Models of Protostars in Orion with Near- to Far-Infrared Observations

During the protostellar stage of star formation, a young star is surrounded by a large infalling envelope of dust and gas; the material falls onto a circumstellar disk and is eventually accreted by the central star. The dust in the disk and envelope emits prominently at infrared wavelengths; by modeling the near- to far-IR spectral energy distributions (SEDs) of protostars, properties of their disks and envelopes can be derived. As part of the Herschel Orion Protostar Survey (HOPS), we have observed over 300 protostars in the Orion star-forming complex at 70 and 160 micron with the PACS instrument on the Herschel Space Observatory. For most objects, we also have photometry in the near-IR (2MASS), mid-IR (Spitzer/IRAC and MIPS), sub-mm (APEX/SABOCA and LABOCA), and Spitzer/IRS spectra. For the interpretation of the SEDs, we have constructed a large grid of protostellar models. In this talk I will explain our SED fitting techniques to determine the best-fit model for each HOPS protostar. I will show how distinct parts of the SED provide different constraints for each fit. I will also present a few examples that illustrate our SED fitting method, as well as some preliminary results on protostellar properties in Orion derived from our fits.